题目
小明很喜欢数学,有一天他在做数学作业时,要求计算出9~16的和,他马上就写出了正确答案是100。但是他并不满足于此,他在想究竟有多少种连续的正数序列的和为100(至少包括两个数)。没多久,他就得到另一组连续正数和为100的序列:18,19,20,21,22。现在把问题交给你,你能不能也很快的找出所有和为S的连续正数序列? Good Luck!
输出描述:
输出所有和为S的连续正数序列。序列内按照从小至大的顺序,序列间按照开始数字从小到大的顺序
算法一:
class Solution {
public:
vector<vector<int> > FindContinuousSequence(int sum) {
vector<vector<int>>s;
if(sum < 3)
return s;
int small = 1;
int big = 2;
int middle = (sum +1)/ 2 ;
int count = small + big;
while(small < middle && big<= middle && small < big)
{
if(count == sum)
{
print(s, small, big);
count -= small;
small++;
}
else if(count < sum)
{
big++;
count += big;
}
else
{
count -= small;
small++;
}
}
return s;
}
void print(vector<vector<int>> &s, int i, int j)
{
vector<int>v;
for(int k = i; k<=j; k++)
v.push_back(k);
s.push_back(v);
}
};
算法二:
class Solution {
public:
vector<vector<int> > findContinuousSequence(int sum) {
vector<vector<int>>cnt;
if(sum <=0 )
return cnt;
int big = (sum >> 1) + 1;
int small = big-1;
int cursum = big + small;
while(small > 0 && small <= big)
{
if(cursum == sum)
{
vector<int>value;
for(int i=small; i<=big; i++)
{
value.push_back(i);
}
cnt.push_back(value);
cursum -= big;
big--;
}
else if(cursum > sum)
{
cursum -= big;
big--;
}
else
{
small--;
cursum +=small;
}
}
return cnt;
}
};